When considering the systemic nature of A2AR expression, it is possible that a soluble part of A2AR circulates as exosomes in the plasma and reflects the activity of cellular A2AR. Herein, we found a low level of soluble A2AR in patients with severe CAD, which perfectly matches the low level of A2AR on PBMCs and the artery tissues of these patients (as has already been reported). The gene discussed is ADORA2A; the disease is coronary artery disorder.